Reverse path imaging and transfixing copying machine

ABSTRACT

A copying machine is provided wherein a heat image is formed on a heat sensitive intermediate member at an imaging station by exposing the same and an original to a heat source. Then the intermediate is moved in one direction to a developing station wherein the image thereon is developed with toner particles and thereafter, the direction of movement of the intermediate is reversed back along the same path to the imaging station whereat a copy medium is brought into engagement with the developed image and heat is applied thereto by the same heat source and the developed image transferred to the copy medium. The heat sensitive intermediate member may be in the form of a continuous web or a cut sheet. Rather than transfer the developed image to a copy paper, the toner particles may be fixed or fused to the heat sensitive member.

United States Patent [1 1 Eichorn, deceased et a1.

[ Sept. 23, 1975 1 REVERSE PATH IMAGING AND TRANSFIXING COPYING MACHINE [75] Inventors: Roger H. Eiehorn, deceased, late of Webster, N.Y.; Lincoln First Bank of Rochester, executor, Rochester,

[73] Assignee: Xerox Corporation, Stamford,

Conn.

[22] Filed: Dec, 27, 1973 21 Appl. No.: 428,956

[52] U.S. Cl 250/316; 250/319 [51] Int. Cl! 841M 5/00 [58] Field of Search 250/316, 317, 318, 319

[5 6] References Cited UNITED STATES PATENTS 3,081,699 3/1963 Gulko 250/318 3,260,612 7/1966 Dulmage 250/317 Primary Examiner-Craig E. Church [57] ABSTRACT A copying machine is provided wherein a heat image is formed on a heat sensitive intermediate member at an imaging station by exposing the same and an original to a heat source. Then the intermediate is moved in one direction to a developing station wherein the image thereon is developed with toner particles and thereafter, the direction of movement of the intermediate is reversed back along the same path to the imaging station whereat a copy medium is brought into engagement with the developed image and heat is applied thereto by the same heat source and the developed image transferred to the copy medium. The heat sensitive intermediate member may be in the form of a continuous web or a cut sheet. Rather than transfer the developed image to a copy paper, the toner particles may be fixed or fused to the heat sensitive member.

15 Claims, 14 Drawing Figures l I [III I III/II US Patent Sept. 23,1975 Sheet 1 of 10 3,908,125

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US Patent Sept. 23,1975 Sheet 4 of 10 3,908,125

CAM MOTOR REVERSIBLE MOTOR CAM REVERSIBLE MOTOR US Patent Sept. 23,1975 Sheet 5 of 10 3,908,125

NIP ROLL OTOR MOTOR M2 FEED ROLLER REVERSIBLE MOTOR Ml REVERSIBLE MOTOR Mlo F/G'JO US Patent Sept. 23,1975 Sheet 6 0f 10 3,908,125

US Patent Sept. 23,1975 Sheet 7 of 10 3,908,125

US Patent Sept. 23,1975 Sheet 8 of 10 3,908,125

Sheet 9 of 1() 1 m wnw A V gm s Iv Rm 3w US Patent US Patent Sept. 23,1975 Sheet 10 of 10 3,908,125

um. m 2 R mM M VACUUM MOTOR M24 FIG. /3

REVERSIBLE MOTOR FEED ROLLER MOTOR M22 L M LR UM4 3 U 2 RT2 CNM M A W VM N CAM MOTOR REVERSIBLE MOTOR i 270 v v I I REVERSE PATH IMAGING AND TRANSFIXING COPYING MACHINE DESCRIPTION OF THE INVENTION In many thermographic processes. a heat image is impressed upon a heat sensitive member at an imaging station and thereafter the image is developed with toner particles and either the toner particles are fused to the heat senstivie material or the toner particles are transfixed (transferred and fused) to a copy medium from the heat sensitive material at a fusing or transfer station downstream of the development station. Separate radiation sources are utilized for the heat imaging function and the fusing or transfer function. In some systems, the same radiation source is utilized for the imaging function as well as the fusing or transfer function at the separate stations.

In the process where two separate radiation sources are utilized, one downstream of the other. separate control mechanisms and transport mechanisms must be provided and must be synchronized so that the functions at each station are efficiently carried out. Obviously, this requires duplication of part and a more complicated system.

When the same radiation source is provided for both stations a web intermediate or heat sensitive material is wasted since a new portion of the web is exposed to the radiation source when the imaged portion of the web is being fused or transferred. Furthermore, one is slimited to the same radiation intensity for both functions or the machine must be larger so that the radiation source may be changed to a different intensity for either fusing or transfixing after imaging.

It is an object of this invention to provide an automated copying method which permits the use of an inexpensive, simple copying device in which there will be no or little waste of the heat sensitive web material and in which the device will be simple and compact.

It is a further object of this invention to provide an automated copying method which permits the use of an inexpensive simple copying device for utilizing heat sensitive material in cut sheet form.

It is proposed to accomplish the above object by using the same radiation source and station for imaging and either fusing or transfixing functions.

Other objects of this invention will become apparent from the following description with reference to the drawings wherein:

FIG. 1 is a general schematic view of one embodiment of a copying apparatus for effecting the concept of this invention while performing imaging and developing functions;

FIG. 2 is a view of the copying apparatus after an image on a web has been developed;

FIG. 3 is a partial view of the copying apparatus during transfer and fixing of a powder image from the web to a copy sheet;

FIG. 4 is a veiw of an electrical schematic ofa system for operating the copying apparatus of FIG. 1 showing the operation thereof during the first phase of an operation cycle;

FIG. 5 is a view of the electrical schematic shown in FIG. 4 showing the operation thereof during the second phase of the operation cycle;

FIG. 6 is a view ofthe electrical schematic shown in FIG. 4 showing the operation thereof during the third phase of the operation cycle;

FIG. 7 is a veiw illustrating the use of the embodiment of FIG. I for making multicolored copies during an imaging step utilizing a separate heat sensitive sheet;

FIG. 8 is a view similar to FIG. 7 during transfer and fixing of a powder image from the separate heat sensitive sheet to a copy sheet.

FIG. 9 is a general schematic view of the copying apparatus shown in FIG. I only modified to include an automatic copy paper feed;

FIG. 10 is a view of an electrical schematic of a system for operating the copying apparatus of FIG. 7 showing the operation thereofduring the second phase of the operation cycle;

FIG. 11 is a schematic view of another copying apparatus embodiment employing the same principles of this invention showing the imaging and developing step;

FIG. I2 is a view of the apparatus of FIG. 9 showing a developed image transfer step;

FIG. 13 is a view of an electrical schematic of a system for operating the copy apparatus of FIGS 9 and 10 showing the operation thereof during the first phase of an operation cycle; and

FIG. 14 is a view of the electrical schematic shown in FIG. II showing the operation thereof during the second phase of the operation cycle.

Referring to FIG. I, a web of heat sensitive material 10 is fed from a supply spool I2 around idler rolls l4, l6, l8, and 20 to a take-up spool 24. The web 10 comprises a support with a heat sensitive coating. For example, the support may be an organic film such as a polyester film, cellulose acetate or triacetate film coated with a delayed tack adhesive which is normally hard and non-tacky at toom temperature, but which. upon being activated by heat to a tacky condition and subsequently cooled to room temperature. thereafter remains tacky for considerable periods of time varying from at least 30 seconds to several days or more depending upon the particular composition involved. Such delayed tack coatings are well known and can be a mixture of discrete particles of resin such as indene resin or csterfied resin and discrete particles of crystalline plasticizer such as diphenyl phthalate or N- cyclohexyl paratoluene sulfonamide. The particles are bound together into the supporting film by a binder such as styrenebutadiene copolymer. Generally speaking, the crystalline plasticizer component of the mixture is in excess of the resin component.

The supply spool 12 and the take-up spool 24 are connected through a respective slip clutch (not shown) to a reversible motor M1 (see FIG. 5 The clutch connection for the supply spool I2 is such that the spool will be positively driven in a counterclockwise direc tion and slips to allow the spool to rotate in a clockwise direction. The clutch connection for the take-up spool 24 is such that the spool will be positively driven in a clockwise direction and slips to allow the spool to re tate in a counterclockwise direction.

A rotatable cylinder 26 having a highly reflective surface and which is reversibly driven by the motot MI is interposed between the idler rolls I6 and 18 and is so arranged that the web 10 is pressed against the idler rolls to form nips l7 and 19. A radiation source such as an incandescent lamp 28 is located opposite the cylinder 26 and a reflector 30 is arranged to focus the rays of the lamp 28 onto the cylinder 26 between the idler rolls l6 and I8.

A developing station is provided which comprises a developer housing 32 having a bed of ferromagnetic toner particles 34 therein. The toner particles 34 com prise thermoplastic particles pigmented with carbon black or other radiation absorbing dyes or pigments. and mixed with iron oxide particles.

A well known magnetic brush 39 is rotatably mounted to the side walls of the housing 32 and located to present toner particles to the web It) as it passes thereby. The magnetic brush 39 is operably connected to the motor Ml to be reversibly driven thereby.

An original inlet slot 36 is provided which opens adjacent the nip 1? and an original outlet and copy inlet slot 38 is provided which opens adjacent the nip I9. A copy outlet opening 40 is provided which is also adjacent the nip 17. A micro-switch MS] is provided in the original inlet opening 36 and a microswitch M82 is located in the copy inlet slot 38 which. when actuated, serves to actuate a control mechanism 42. A pair of nip rolls 37 are provided in the opening 38 and are driven in one direction by motor M1 to discharge an original from the copying apparatus and are driven in the opposite direction to pull a copy paper into the machine.

The reversible motor M1 has a forward input terminal 44 connected to a power source 46, a forward input terminal 48 connected to ground, a reverse input terminal 50 connected to the power source 46 and a reverse input terminal 52 connected to ground. Cam operated switches S1 and S2 are located to control the communicaton of the power source with the forward input terminal 44 and the reverse input terminal 50, respectively. The lamp 28 is connected to the power source 46 and a cam operated switch 53 controls the communication thercbetween. A cam motor is connected to the power source 46 and a cam operated switch S4 controls the communication therebetween. Microswitches M81 and M82 also control the communication between the power source 46 and the cam motor. The cam motor drives a shaft in one direction which has a plurality of cams C1, C2, C3 and C4 fixedly secured thereto which are arranged to actuate switches SI, S2, S3 and S4, respectively. during one complete revolution through phases A, B and C of one cycle of machine operation. Cam Cl has cam surfaces A and C which close switch 81 during rotation of the cams through A and C phases. Cam C2 has a cam surface B which closes switch S2 during rotation of the cams through the 8 phase. Cam C3 has cam surfaces A and B which close switch S3 during rotation of the cams through the A and B phases. Cam C4 has cam surfaces A and BC which close switch S4 during the A. B and C phases.

The operation of the apparatus is as follows:

Referring to FIGS. I and 4. an original sheet 54 having an image thereon is fed into the inlet slot 36 actuating the microswitch MSl which connects the cam motor with the power source 46 and sets the cam bank into clockwise rotation. As soon as the cam bank begins rotation, the cam surface A of cam Cl closes switch S1 to actuate motor MI in the forward direction to rotate the web take-up spool 24. the cylinder 26, the magnetic brush 39 and the nip rolls 37 in the direction indicated by the arrows in FIG. I. At the same time, the cam surface A of cam C4 closes the switch S4 to lock in communication of the cam motor to the power source 46. Also at the same time, the cam surface A of cam C3 closes the switch S3 to energize the lamp 28. The leading edge of the original sheet 54 is fed into the nip [7 and is moved with the web I0 past the lamp and then the original separates from the web and is directed through the outlet opening 38. The switch MSZ located in the outlet opening is a one way switch and is not actuated by the original as it travels therepast. As the web 10 and the original 54 pass the lamp 28 and around the cylinder 26, the sandwich is in tight engagement with the cylinder 26 assuring efficient heat transfer between the image and the heat senstive layer whereby the radiant rays are absorbed by the image forming a heated image which is transferred to the heat sensitive web 10 to form a tacky image corresponding to the image on the original sheet. The web is transported past the magnetic brush 39 which presents toner particles to the web and develops the tacky image thereon. The cam surface A on cam C3 is designed to allow the switch S3 to open approximately after the imaging function has been completed thereby dc-cnergizing the lamp 28. The cam surface A of cam Cl is designed to allow switch S1 to open and stop the drive motor M1 and thereby the take-up shaft 24, the cylinder 26. the nip rolls 37, and the magnetic brush 39 when a sufficient length of the web I0 corresponding to the length of the sheet to be copied passes at least the magnetic brush 39 with a portion of the leading edge of the developed image being wrapped on the take-up roll 24 as a single layer only to avoid any smudging of the developed image. To illustrate this. reference is made to FIG. 2 where the leading edge of the developed image is indicated by reference numeral 58 and the trailing edge indicated by reference numeral 60. The cam surface A of cam C4 is designed to allow switch S4 to open immediately after switch S1 is open to stop the cam motor. At this point, the cam bank has turned approximately onethird of a revolution.

Referring now to FIGS. 3 and 5, the operator inserts a copy sheet 56 into the copy slot 38 which actuates switch MS2 which connects the cam motor to the power source 46 and thereby starts the cam bank rotating again. As soon as the cam bank starts rotating. the cam surface B of cam C2 closes switch S2 to energize motor MI in the reverse direction thereby rotating the supply shaft 12. the cylinder 26, the nip rolls 37, and the magnetic brush 39 in the direction as shown by the arrows in FIG. 3. At the same time, the cam surface BC of cam C4 closes switch S4 to lock in communication between the power source 46 and the cam motor. Cam surface B of C3 is so located to close switch S3 to energize the lamp 28 at approximately the time just prior to the leading edge of the copy sheet 56 entering the nip 19. The web 10 starts its reverse movement with the former trailing edge 60 now being the leading edge. As the leading edge 60 of the image moves toward the nip 19, the copy sheet 56 is moved toward the nip I9 by the nip rolls 37 and so timed that the leading edge of the copy sheet 56 will align with the leading edge 60 of the image just prior to entering the nip 19. The aligned copy sheet and the image on the heat senstive web are forwarded past the lamp 28 whereby the rays therefrom heat the toner particles whereby a substantial portion thereof are transfixed (transfer and become fixed) to the copy sheet to provide a reproduction of the original image. This transfer occurs due to the pressure between the web 10 and the copy sheet 56 effected as they travel around the cylinder 26 and effected at the nip 17 combined with a corresponding proper temperature. As the copy sheet 56 emerges from the nip 17, the

sheet separates from the web and is directed out of the machine through the slot 40. The cam surface B of cam C3 is so designed to allow switch S3 to cut off communication between the lamp 28 and the power source 46 immediately after the trailing edge of the copy sheet 56 emerges from the mip 17. The cam surface B of cam C2 is so designed to allow switch S2 to open to cut off communication between the power source and the motor Ml at the same time that the lamp 28 is turned off to stop rotation of the supply shaft 12, the cylinder 26, the nip rolls 37 and the magnetic brush 39. At this point of the operation, the cam shaft has rotated approximately two-thirds of a revolution.

Referring to FIG. 6, the cam surface BC of cam C4 is so designed to maintain switch S4 closed and thereby keep the cam motor turning the cam bank which results in cam surface C of cam Cl closing switch S1 to communicate motor M1 to the power source 46 to drive the motor in the forward direction which drives the web take-up shaft 24, the cylinder 26, the nip rolls 37 and the magnetic brush 39 in the direction as shown in FIG. 1. The cam surface C of cam Cl is so designed to maintain the switch 8] closed and therefore the motor Ml driving in a forward direction until the edge 60 of the used portion of the web is transported to just beyond the nip 17 whereby a fresh portion of the web is in position to be used when a new copy is to be made. The cam BC of cam C4 so so designed to keep the switch S4 closed and thereby the cam bank rotating until just after the switch S1 is opened. At this point, a full cycle of operation of the copying apparatus has been completed and the cam bank has rotated one complete revolution.

Rather than insert a copy sheet into the original outlet slot. 21 separate copy inlet slot with microswitch M82 therein could be provided. Also, a safety switch may be employed in series with microswitch M82 in the reverse direction in case the copy sheet is inserted prior to the motor Ml being stopped after phase A. In this case, a cam can close the safety switch to energize the motor M1 in the reverse direction after motor Ml has stopped at the completion of phase A.

Referring to FIGS. 7 and 8, the copying apparatus may be used in another manner illustrated. It may be desired to make a multicolored copy of the original 54. In this instance, the original 54 and a heat sensitive sheet [0' are fed into the inlet slot l7 as a sandwich actuating the microswitch MS] which starts the machine operation as previously described. The sandwich is fed past the rays from lamp 28 imparting a heat image on the sheet 10'. The sandwich is discharged out of the slot 38 and the sheets separated by the operator. The operator then dusts by hand toner particles over the developed image in any manner he wishes and in any color pattern. The operator then takes the developed sheet 10 and a copy sheet 56' and introduces the same as a sandwich into the slot 38 which actuates microswitch MS2 which reverses the copying apparatus in the manner described above. The sandwich is fed past the lamp rays of lamp 28 whereby the toner particles are transferred to the copy sheet 56. The sandwich is then discharged through the slot 40 and the sheets are separated by the operator. A special control can be provided to be set by the operator which will prevent the machine from operating during rotation of the cam bank through the third phase. since the web 10 does not become tacky, the toner particles 34 presented by magnetic brush 39 do not stick thereto. Therefore the web 10 is in position to be used again in the normal manner without any waste being effected during this copying process. Rather than transfer the toner to a copy sheet, the toner could be fused to the sheet [0' by passing that sheet alone into the slot 38 and out of the slot 40.

Referring to FIG. 9, there is illustrated a modification of the copying apparatus of FIG. 1 wherein the copying apparatus has been provided with a paper tray for automatic paper feed. All elements which operate in the same manner as the described in the previous embodiment are illustrated with the same reference numeral only with an a affixed thereto. A stack of copy sheets 100 is located on a paper tray I02. The stack of sheets are urged by a torsion spring 104 against a paper feed roll l06. The paper feed roll I06 drives the uppermost sheet of the stack along a guide 108 to a pair of nip rolls "0 which receive the leading edge of the copy sheet therein. A motor M2 is operably connected to the paper feed roll 106 for driving the same and a motor M3 is operably connected to the nip rolls 1 [0 for driving the same.

Referring to FIG. 10, an electrical diagram for oper ating this modified machine is disclosed. All elements which operate in the same manner as in the previous embodiment are designated by the same reference numerals only with an a affixed thereto. A cam operated switch S5 is arranged to control communication between the motor M2 and the power source 460 and a cam operated switch S6 is arranged to control communication between the motor M3 and the power source 46a. Cams C5 and C6 are arranged to actuate the switches and S6 respectively. Cam surface 8 on cam C5 is so designed to close the switch S5 to communicate motor M2 to the power source 46a at the same time that cam C2u closes switch S2 to cause reversing of the motor Mla. The actuation of the feed roll a06 by the motor M2 drives the uppermost sheet of the stack along the guide 108 to the nip rolls 110. A storage recesss 112 is provided in the guide 108 to allow the sheet to buckle until the nip rolls 110 are actuated. The cam surface 8 on cam C6 so designed to close switch S6 to actuate the motor M3 and thereby the nip rolls 110 at the proper time so that the leading edge of the copy sheet will align with the leading edge 56a of the developed image just prior to entering the nip 19a. The cam surface B of the cam C5 is designed to allow the switch S5 to open and cut off communication between the motor M2 and the power supply 460 immediately after the feed roll 106 has discharged the uppermost copy sheet from the stack of copy papers 100. The cam surface B of cam C6 is so designed to allow switch S6 to open to cut off communication between the power source 460 and the motor M3 and thereby stop nip rolls "0 after the trailing edge of the copy sheet is discharged through the nip rolls.

Rather than transfer the developed image to a copy paper, the developed image may be fused onto the heat sensitive webs l0 and 100 or the heat sensitive sheet 10'. This may be desired when a series of copies are needed in a specified sequence. In this case, the copy paper is eliminated and the toner particles are fused to the heat sensitive webs l0 and 10a or the heat sensitive sheet 10' when they are exposed to the lamp 28 or 28a when moving therepast in the reverse direction shown in either FIGS. 3, 8, or 9. [n this respect, the surface of the cylinders 26, 2611 which will be contacted during the fixing or fusing step by the toner particles must comprise a material to which melted toner particles will not stick. Alternatively, a release sheet could be substituted for the copy sheet 56 in H08. 3 and 8 or a stack of release sheets could be placed on the paper tray 102 in FlG. 9 and fed past the lamps 28 or 280 in contact with the developed image. in this instance. the release sheet will be of a material to which the toner particles will not stick.

Referring to FIG. 11, the same principle utilized for the previous embodiments is applied for making copies when utilizing heat sensitive members in cut sheet form. In this embodiment, a copying apparatus 200 has a guide slot 212 for receiving a sandwich of a heat sensitive sheet 214 and an original sheet 216 with an image thereon. A cylinder 218 having a highly reflective surface is rotatably mounted on the frame of the machine and a transparent belt 220 rotates around three idler rolls 222, 224, 228, and a drive roll 226. The cylinder 218 and the drive roll 226 are driven by a reversible motor M21. The rolls 224 and 226 are arranged that the belt 220 is pressed against the cylinder 218 to form nips 22S and 227, respectively. A microswitch MS21 is located in the slot 212 and is electrically connected to the reversible motor M21 for starting the same and is arranged to be actuated upon insertion of sheets into the slot. Upon rotation of the cylinder 218, the belt 220 will be rotated therewith and pressed against the surface of the cylinder. An incandescent lamp 230 is arranged opposite the cylinder 218 to apply radiant rays to the region of the cylinder 218 which is opposite the lamp. Upon insertion of the original sheets 216 and the heat sensitive member 214 as a sandwich into the slot 212 and into engagement with the nip 227, the sandwich will be pulled past the lamp 230. A slot 231 is provided through which the original sheet 216 emerges after being separated from sheet 14. A sheet separator 233 is located at the entrance of the slot 231 and is under vacuum during a period necessary to attract the original thereto thereby separating the same from the heat sensitive sheet 214. A motor M24 is provided for effecting the vacuum at sheet separator 233.

A conveyor mechanism, which comprises a belt 232 arranged around a drive roll 234 and an idler roll 236, is located to coact with a roll 238 wich forms a pressure nip therebetween to grip the leading edge 239 of the heat sensitive sheet 214 to drive the same along a guide member 240 to a developer station which comprises a housing 241 having ferromagnetic toner particles 242 therein. The drive roll 234 is driven by the motor M21. A well known magnetic brush 244 is mounted on the housing 241 to have a portion rotatable in the toner bed 242 and a portion arranged to engage the heat sensitive sheet 214 to present toner thereto to develop the image thereon. The magnetic brush 244 is also connected to the reversible motor M21 which drives the cylinder 218 and the drive roll 234.

A storage slot 250 is provided to receive the leading edge 239 of the heat sensitive sheet 214 after the Same has passed the development station. The idler roll 236 is arranged relative to the surfade 251 of the slot 250 that the belt 232 is spaced from the surface 251 less than the thickness of the sheet 214 to grip the heat sensitive sheet 14 therebetween to move the same. ;A supply of copy paper 254 is arranged on a paper tray 256 and a feed roll 258 is arranged to engage the uppermost one of the stack of copy papers 254 to drive the same away from the stack along a guide member 260 to a pair of nip rolls 262. A torsion spring 261 biases the paper tray 256 toward the feed roll 258 and thereby brings the stack of copy paper into engagement with the feed roll. A motor M22 is provided for driving the feed roll 258 and a motor M23 is provided for driving the nip rolls 262.

Referring to FIG. 13, there is shown an electrical control diagram for operating the apparatus of the embodiment of FIGS. 11 and 12. The reversible motor M21 has a forward input terminal 268 connected to a power source 270, a forward input terminal 272 connected to ground, a reverse input terminal 274 connected to the power source 270 and a reverse input terminal 276- connected to ground. Cam operated switches S21 and S22 are located to control the communication of the power source with the reverse input terminal 274 and the forward input terminal 268, respectively. The lamp 230 is connected to the power source 270 and a cam operated switch 823 controls the communication therebetween and a cam motor is connected to the power source 270 and a cam operated switch S24 controls the communication therebetween. The motors M22, M23, and M24 are connected to the power source 270 and cam operated switches S25, S26, and S27 control the communication therebetween, respectively. The cam motor drives a shaft in one direction which has aplurality of cams C21, C22, C23, C24, C25, C26, andlC27 fixedly secured thereto which are arranged to actuate switches S21, S22, S23, S24, S25, S26, and S27, respectively. during one complete revolution through phases A and B of one cycle of machine operation. Microswitch MS21 also controls communication of the power source 270 to the cam motor.

Cam C22 and C27 each has a cam surface A which closes switches S22 and S27, respectively. during rotation of the cam bank through the A phase of the cycle. Cams C21, C25 and C26 each has a cam surface 8 which closes switches S21, S25, and S26, respectively during rotation of the cam bank through the B phase of the cycle. Cam C23 has cam surfaces A and B which close switch S23 during rotation of the cam bank through the A and B phases of the cycle. Cam C24 has cam surface AB which closes switch S24 during rotation of the cam bank through the A and B phases of the cycle.

The operation of the apparatus is as follows: referring to FIGS. 11 and 13, a heat sensitive sheet 214 and an original sheet 216, having an image thereon to be copied. are placed together to form a sandwich and inserted into the slot 212 to actuate the microswitch MS21 which connects the cam motor with the power source 270 and sets the cam bank into clockwise rotation. As soon as the cam bank begins rotation, the cam surface A of cam C22 closes switch 822 to actuate motor M21 in the forward direction to rotate the cylinder 218, belt 232, and the magnetic brush 244 in the direction indicated by the arrows in FIG. 11. At the same time, the cam surface A of cam C24 closes switch S24 to lock in communication of the cam motor to the power source 270. Also at the same time, the cam surface A ofeam C23 closes the switch 823 to energize the lamp 230 and the cam surface A of cam C27 closes the switch 827 to energize the motor M24 and effect a vacuum atseparator 233. The sandwich is fed between the cylinder 218 and the belt 220 past the incandescent lamp 230 and is exposed to the rays of the lamp 230. The intensity of the lamp and the speed at which the sandwich passes thereby is such as to cause sufficient heat to effect a tacky image on the heat sensitive member corresponding to the image on the original sheet 216. As the leading edge of the sandwich emerges from between the belt 220 and the cylinder 218, the original is separated from the heat sensitive sheet 214 by vacuum separator 233 and is discharged from the copying apparatus through the slot 231. The heat sensitive sheet 214 continues to the development station whereby the magnetic brush 244 dusts toner particles 242 onto the tacky image and then passes into the storage slot 250. The cam surface A of cam C22 is designed that the trailing edge 253 of the heat sensitive sheet 214 will have passed the magnetic brush 244 prior to allowing switch 822 to open and stop motor M21. The cam surface A on cam C23 is designed to allow switch S23 to open and thereby de-energize the lamp 230 after the sandwich has been discharged through the nip 227. The cam surface A on cam C27 is designed to allow switch S27 to open to stop the vacuum motor M24 at about the same time that the motor M21 is stopped. The cam surface AB on cam C24 is designed to keep ths switch S24 closed to keep the cam motor actuated and thereby the cam bank turning after the switch S22 is opened. At this point, the cam bank has turned approximately one-half of a revolution.

Referring now to FIGS. 12 and 14, continued rotation of the cam bank effects closing of the switch S2] by the cam surface B on cam C21 thereby starting motor M21 in the reverse direction thereby causing reversal of rotation of the belt 232, the magnetic brush 244, and the cylinder 218. At the same time. the cam surface B of cam C25 closes switch S25 to actuate the motor m22 and thereby start rotation of the paper feed roll 258. Upon reversal of the belt 232, the heat sensitive sheet 214 is removed out of the storage area 250 with the former trailing edge 253 now being the leading edge. The sheet 2l4 is passed through the developer station wherein magnetic brush 244 presents particles to the image to develop the image with more toner particles if necessary. At this point, the leading edge of a copy paper 154 has been moved to the nip rolls 262 and the cam surface B of cam C26 closes switch S26 to energize the motor M23 and thereby rotate the nip rolls 262 in the direction as shown in FIG. 12 to drive the copy sheet 254 to arrive just prior to the nip 227 at the same time as former trailing edge 253, but now the leading edge, of the heat sensitive sheet 214 arrives thereat so the two sheets will be aligned. Cam surface 8 of cam C23 closes switch S23 to energize the lamp 230 just prior to the time that the leading edges of the copy sheet 254 and the heat sensitive sheet 214 enter the nip 227. The two sheets enter the nip 227 between the cylinder 218 and the belt 220 as an aligned sandwich and are exposed to the incandescent lamp 230 for a sufficient time to melt the toner particles whereby a substantial portion thereof will transfer to the copy sheet 254 to provide a reproduction of the original image. The heat and the slight pressure between the sheets caused by the pressure between the belt 220 and cylinder 218 effects transfer and the fixing of the toner particles to the copy sheet 254. Then the sandwich is passed out of the copying apparatus through the slot 212 whereby an operator takes the sandwich and separates the sheets to obtain the copy of the image on the original. The cam surfaces B of cams C21. C23. and C26 are designed to allow the switches S21. S23. and S26 to open and thereby shut off their respective motors after the sandwich is discharged through slot 2l2. The cam surface B on cam C25 is arranged to allow switch S25 to shut off motor M22 and thereby stop rotation of the paper feed roll 258 after the feed roll has discharged the uppermost copy sheet from the stack of copy papers 254. The cam surface AB of cam C24 is designed to allow switch S24 to open after all other switches are open to thereby stop the cam motor and the rotation of the cam bank to complete the cycle of operation.

Rather than using a paper tray, this embodiment could be modified by eliminating the paper tray 256 and its associated parts and a copy sheet could be inserted into original outlet slot 23] or a new copy inlet could be provided. The slot would have nip rolls arranged similar to nip rolls 37 of the embodiment of FIG. 1. In this instance. a microswitch could be located to be actuated by the copy sheet. The control circuit would be modified whereby the cam motor is inactivated after the first phase and then is activated upon closing the microswitch by the copy sheet.

Rather than transfer the developed image to a copy sheet, the developed image may be fixed to the heat sensitive sheet 214 with the heat sensitive sheet being the copy itself. In this respect, the surface of the cylinder 218 which will be contacted by the toner particles during the fixing or fusing step must comprise a material to which melted toner particles will not stick. Alternatively, a stack of release sheets could be placed on the paper tray 256 and fed past the lamp 230 in contact with the developed image. In this respect. the release sheet will be of a material to which the toner particles will not stick.

From the above, it can be seen that compact and simple copying apparatus has been invented. furthermore, since the imaging and developing function of the components of the embodiments described is separate from the image transfer or fusing function, the intensity of the lamps 28, 28a. and 230 and the speed at which the webs l0, and 10a and sheet 214 travel in reverse can be changed from the intensity and speed for the imaging and developing function depending upon for what results a particular apparatus machine is designed.

The connection of the motors to their respective elements which they drive have not been shown as these are all well known and well within the grasp of one having ordinary skill in the art.

What is claimed is:

l. A thermographic copier comprising the combination of a radiant source for supplying radiant energy to a first station via a predetermined path. a development station spaced from said first station, reversible transport means for advancing a heat sensitive member through said first station in one direction to thermally impart an image thereto and for continuing movement of said heat sensitive member in said one direction through said development station to develop said image and for then moving said heat sensitive member back in the opposite direction through said first station to produce a substantially permanent copy of said image, a copy supply tray, means for moving a copy member out of said tray and into contact with said heat sensitive member at a location between said development station and said first station when said heat sensitive member is moving in said opposite direction. and means for selectively energizing said radiant source in prepara tion for the passage of said heat sensitive member through said first station is said one and said opposite directions.

2. The copier ofclaim I further comprising means for discharging the copy member and the heat sensitive member from the copier after they have passed through said first station in said opposite direction.

3. A thermographic copier comprising the combination of a radiant source for supplying a heating station with radiant energy, reversible drive means for convcy ing an image bearing subject and a heat sensitive mem her through said heating station in one direction so that said image is thermally imparted to said member and for conveying at least the heat sensitive back through said heating station in the opposite direction. a storage area. a development station located between said heating station and said storage area, and means located between said development station and said heating station for separating the subject and heat sensitive member after they pass said heating station in said one direction; said drive means including means for continuing the movement of said heat sensitive member in said one direction after separation from said subject so that said heat sensitive member is conveyed past said development station for development of said thermally im parted image and into said storage area. and means for subsequently conveying said heat sensitive member in the opposite direction back through said development station and said heating station to fuse the developed image.

4. A copier as recited in claim 3 wherein the developed image is transfixed onto a a copy paper as said heat sensitive member moves through said heating station in said opposite direction.

5. A thermographic copier comprising the combination of a source for supplying radiant energy to a heating station via a predetermined path. a development station spaced from said heating station. a heat sensitive web extending through said heating and development stations. reversible drive means for selectively moving said web in one direction and in the opposite direction. control means for actuating said drive means to sequentially move a portion of said web through said heating station and said development station in said one direction and to then move said portion of said web back through said heating station in the opposite direction. and means for energizing said radiant source while said portion of said web is passing through said heating station in either of said directions.

6. The copier of claim 5 wherein said drive means includes means for presenting an unused portion of said web for each successive copying cycle.

7. The copier ot'claim 5 further comprising means for bringing a member bearing an original image into contact with said portion of said web. said reversible drive means including means for moving the image bearing member and said portion of said web through said heating station in said one direction. and means located between said development station and said heating station for separating the image bearing member from said web before moving said portion of said web through said development station.

8. The copier of claim 7 further comprising means for bringing a copy member into contact with said portion of said web after said web has completed movement in said one direction. said drive means including means for moving the copy member and said portion of said web through said heating station in said opposite direc tion.

9. The copier of claim 8 further comprising means responsive to motion of a copy member toward said web for reversing said drive means to move said web portion in said opposite direction.

[0. The copier of claim 7 further comprising an inlet opening for feeding said image bearing member into contact with said web at a location upstream of said heating station. an outlet opening. and means located between said development station and said heating station for separating said image bearing member from said web during movement of said web in said one direction and for feeding said image bearing member out of said copier via said outlet opening.

11. The copier of claim 10 further comprising a copy member supply tray. and means for moving a copy member out of said tray and into contact with said web portion at a location between said development station and said heating station when said web portion is moving in said opposite direction.

[2. The copier of claim [0 wherein said outlet opening also serves to feed a copy member toward said web 13. The copier of claim 12 further comprising means responsive to the feed of a copy member through said outlet opening for reversing said drive means to move said web portion in said opposite direction.

14. A thermographic copier comprising the combination of a radiant source for imaging and fusing at a common heating station. a development station spaced from said heating station. a heat sensitive web extending through said heating station and said development station. reversible drive means for moving said web first in one direction and then in the opposite direction, means for bringing a first sandwich containing a member with an original image thereon and a heat sensitive member into contact with said web to move with said web through said heating station in said one direction. means located between said development station and said heating station for separating the first sandwich from said web after they pass said heating station while traveling in said one direction. means for bringing a second sandwich containing a copy member and a heat sensitive member bearing a developed image into contact with said web at location between said development station and said heating station to move with said web through said heating station in said opposite direction, means for separating the second sandwich from said web and for discharging said second sandwich from the copier and means for energizing said radiant source when said web moves in each of said directions, whereby imaging takes place as said web moves in said one direction and fusing takes place as said web moves in the opposite direction.

[5. The copier of claim 14 further comprising means responsive to the appearance of said second sandwich in the copier for reversing said drive means to move said web and said second sandwich in said opposite direction. 

1. A thermographic copier comprising the combination of a radiant source for supplying radiant energy to a first station via a predetermined path, a development station spaced from said first station, reversible transport Means for advancing a heat sensitive member through said first station in one direction to thermally impart an image thereto and for continuing movement of said heat sensitive member in said one direction through said development station to develop said image and for then moving said heat sensitive member back in the opposite direction through said first station to produce a substantially permanent copy of said image, a copy supply tray, means for moving a copy member out of said tray and into contact with said heat sensitive member at a location between said development station and said first station when said heat sensitive member is moving in said opposite direction, and means for selectively energizing said radiant source in preparation for the passage of said heat sensitive member through said first station is said one and said opposite directions.
 2. The copier of claim 1 further comprising means for discharging the copy member and the heat sensitive member from the copier after they have passed through said first station in said opposite direction.
 3. A thermographic copier comprising the combination of a radiant source for supplying a heating station with radiant energy, reversible drive means for conveying an image bearing subject and a heat sensitive member through said heating station in one direction so that said image is thermally imparted to said member and for conveying at least the heat sensitive back through said heating station in the opposite direction, a storage area, a development station located between said heating station and said storage area, and means located between said development station and said heating station for separating the subject and heat sensitive member after they pass said heating station in said one direction; said drive means including means for continuing the movement of said heat sensitive member in said one direction after separation from said subject so that said heat sensitive member is conveyed past said development station for development of said thermally imparted image and into said storage area, and means for subsequently conveying said heat sensitive member in the opposite direction back through said development station and said heating station to fuse the developed image.
 4. A copier as recited in claim 3 wherein the developed image is transfixed onto a a copy paper as said heat sensitive member moves through said heating station in said opposite direction.
 5. A thermographic copier comprising the combination of a source for supplying radiant energy to a heating station via a predetermined path, a development station spaced from said heating station, a heat sensitive web extending through said heating and development stations, reversible drive means for selectively moving said web in one direction and in the opposite direction, control means for actuating said drive means to sequentially move a portion of said web through said heating station and said development station in said one direction and to then move said portion of said web back through said heating station in the opposite direction, and means for energizing said radiant source while said portion of said web is passing through said heating station in either of said directions.
 6. The copier of claim 5 wherein said drive means includes means for presenting an unused portion of said web for each successive copying cycle.
 7. The copier of claim 5 further comprising means for bringing a member bearing an original image into contact with said portion of said web, said reversible drive means including means for moving the image bearing member and said portion of said web through said heating station in said one direction, and means located between said development station and said heating station for separating the image bearing member from said web before moving said portion of said web through said development station.
 8. The copier of claim 7 further comprising means for bringing a copy member into contact with said portion of said weB after said web has completed movement in said one direction, said drive means including means for moving the copy member and said portion of said web through said heating station in said opposite direction.
 9. The copier of claim 8 further comprising means responsive to motion of a copy member toward said web for reversing said drive means to move said web portion in said opposite direction.
 10. The copier of claim 7 further comprising an inlet opening for feeding said image bearing member into contact with said web at a location upstream of said heating station, an outlet opening, and means located between said development station and said heating station for separating said image bearing member from said web during movement of said web in said one direction and for feeding said image bearing member out of said copier via said outlet opening.
 11. The copier of claim 10 further comprising a copy member supply tray, and means for moving a copy member out of said tray and into contact with said web portion at a location between said development station and said heating station when said web portion is moving in said opposite direction.
 12. The copier of claim 10 wherein said outlet opening also serves to feed a copy member toward said web
 13. The copier of claim 12 further comprising means responsive to the feed of a copy member through said outlet opening for reversing said drive means to move said web portion in said opposite direction.
 14. A thermographic copier comprising the combination of a radiant source for imaging and fusing at a common heating station, a development station spaced from said heating station, a heat sensitive web extending through said heating station and said development station, reversible drive means for moving said web first in one direction and then in the opposite direction, means for bringing a first sandwich containing a member with an original image thereon and a heat sensitive member into contact with said web to move with said web through said heating station in said one direction, means located between said development station and said heating station for separating the first sandwich from said web after they pass said heating station while traveling in said one direction, means for bringing a second sandwich containing a copy member and a heat sensitive member bearing a developed image into contact with said web at location between said development station and said heating station to move with said web through said heating station in said opposite direction, means for separating the second sandwich from said web and for discharging said second sandwich from the copier and means for energizing said radiant source when said web moves in each of said directions, whereby imaging takes place as said web moves in said one direction and fusing takes place as said web moves in the opposite direction.
 15. The copier of claim 14 further comprising means responsive to the appearance of said second sandwich in the copier for reversing said drive means to move said web and said second sandwich in said opposite direction. 